1. Field of the Invention
The present invention relates to a fryer for heating up an oil vessel with a heating means to carry out fry cooking.
2. Description of the Related Art
A fryer comprises an oil vessel, a heating means such as a pulse burner for heating up cooking oil (referred to as oil hereinafter) filled in the oil vessel, and a first temperature sensing means such as a thermistor for sensing the temperature of the oil in the oil vessel. The fryer also includes a first controller provided as acting as a temperature setting means for setting the temperature and the cooking time for each menu and equipped with a control panel for controlling and displaying the setting temperature, the menus, and so on, and a second controller arranged responsive to a measurement of the temperature received from the first temperature sensing means for controlling the combustion of the heating means to maintain the oil temperature to the preset setting temperature determined by the first controller.
Moreover, the fryer has a second temperature sensing means such as a bimetal thermostat for preventing continuation of the combustion in case the first temperature sensing means is out of order and its measurement is lower than the actual temperature, and an overheat protecting means for canceling the combustion of the burner when overheating is detected. Thus, the fryer also has an operation test function for examining whether the overheat protecting means properly operates or not. More specifically, when a high limitswitch provided in the control panel of the first controller is turned on, it examines whether or not the pulse burner starts and continues the combustion until the thermostat is switched on and stops the combustion at a predetermined temperature when the thermostat is switched off.
Because the plural controllers communicate with each other with a serial link system, not a parallel link system, which decreases the number of the transmission lines, the overall structure can be simplified. However, using the serial link system may cause the setting temperature to exceed a normally acceptable level because of a wrong setting of the temperature at the control panel of the first controller by an operator. For compensation, an abnormal stopping means can be provided which can cancel the combustion of the pulse burner when the thermistor detects that the temperature exceeds a normally acceptable level. This safety function, however, keeps the pulse burner from continuing the combustion when the operation test for the overheat protecting means is ordered, thereby preventing the operation test for the overheat protecting means from being performed properly.
It is thus an object of the present invention, as defined in claim 1, to provide a fryer which can properly carry out an operation test for the overheat protecting means with a safety function provided for canceling the combustion when the setting temperature exceeds a normally acceptable level, hence improving its utility.
For achievement of the object, the fryer defined in claim 1 of the present invention is modified having an abnormal stopping means for canceling the action of the heating means, regardless of the setting temperature, when the temperature of the oil measured by the first temperature sensing means reaches a specified first upper limit, an overheat protecting means for canceling the action of the heating means when the temperature of the oil measured by the second temperature sensing means reaches a second upper limit which is higher than the first upper limit, and an operation testing means for continuously actuating the heating means to carry out an operation test for the overheat protectingmeans, wherein the action of the abnormal stopping means can be prohibited while the operation testing means is actuated.